Light emitting diode (LED) light strips can provide markings in dimly lit environments. LED light strips are relatively inexpensive, easy to install, and exhibit long life when compared to similar bulb or lamp based markers. Many varieties of LED light strips and manufacturing methods are well known and widely available.
When using a LED light strip on a bicycle, it is imperative that the LED, and associated circuitry housed within the strip, is protected from damage due to loads and impact upon the strip and also from exposure to moisture ingress. However, many conventional LED light strips include circuitry housed within hollow tube-like sheathings which provide only minimal protection against mechanical damage to the circuitry due to excessive loads placed on the sheathings. For example see U.S. Pat. No. 6,846,094 entitled “Flexible LED Lighting Strip” and assigned to Altman Stage Lighting Co., Inc., the disclosure of which is expressly incorporated herein in its entirety by reference. Also, as the tube-like sheathings are hollow, the LED strips are typically susceptible to damage caused by moisture penetration. As a result, such LED light strips are often not desirable for outdoor lighting applications or other applications in which the LED strips are exposed to extreme weather conditions or abuse.
Another conventional light strip includes a multi-layer electroluminescent (EL) lamp configuration sealed through a conventional sheet or hard lamination process. In this hard lamination process, a top layer of protective film is either adhesively bonded or thermally fused to a bottom layer of protective film through the use of high temperatures and high pressure rollers to sandwich the EL lamp configuration between the layers. Such an EL light strip provides a more permanent type of protective sheathing than the above mentioned tube-like sheathing associated with other conventional EL light strips, and provides a more effective moisture barrier. However, moisture is often capable of penetrating into the interior of these two-piece EL light strips through the fused or bonded seal joining the two-piece housing, especially when the strips are used in outdoor applications, or after the bonded or fused seal connecting the two-piece housing weakens over time. In addition, the hard lamination process used to seal the EL lamp configuration is not desirable for LED circuitry, as LEDs are typically greater in height than the substantially flat layers forming the EL lamp configuration. High pressure rollers typically used to bond or fuse the two-piece housing could crush the protruding LEDs during formation of the strip. In addition, the high temperatures required for the bonding or fusing of the strip would subject the LEDs and associated circuitry to heat damage.
Commodity LED Light strips are also commonly manufactured using a two-part coating or encapsulation process. For example, a flexible circuit with LEDs is placed into a pre-extruded rubber trough. The trough is then filled with a liquid RTV compound that hardens into a flexible rubber. Just as with the EL lamps, the two layers of rubber can easily separate from each other or from the flexible circuit under physical stress, or do not effectively seal moisture.
Processes for effective and durable continuous extruded LED light strips have also been developed. For example, see U.S. Pat. No. 6,673,293 entitled “Automated System and Method for Manufacturing an LED Light Strip Having an Integrally Formed Connector” and assigned to Cooper Technology Services, LLC, the disclosure of which is expressly incorporated herein in its entirety by reference. The '293 patent discloses a continuous extrusion process which produces integrally formed single-piece encapsulated strips that have no internal voids, and thereby provide a high degree of protection against damage due to loads placed on the strips and are highly resistant to moisture ingress. This process provides an integrally formed LED light strip that includes fully encapsulated LED circuitry connected to a substrate that exhibits superior bonding characteristics with the extruded light strip housing, thereby providing a high degree of protection from moisture ingress and thereby increasing the functional life of the strip itself. Other examples of such extruded strips are disclosed in U.S. Pat. No. 5,927,845 entitled “Integrally Formed Linear Light Strip With Light Emitting Diodes” and assigned to StanTech, and in pending U.S. Pat. No. 5,848,837 entitled “Integrally Formed Linear Light Strip With Light Emitting Diodes” and assigned to StanTech, the disclosures of which are expressly incorporated herein in their entireties by reference.
Prior art LED light strips, including those disclosed by the '293 patent, do not effectively address durability, flex and environmental protection of an electrical connection at their end or ends. A key element of any light strip is that it is powered and controlled electrically from one or both ends. Many light strips such as those disclosed in the '094 patent are intended for room, stage or building-sized installations and provide a rigid electrical connector at the end of a long flexible light strip. In a comparatively small installation such as a bicycle, a rigid electrical connector at the end of the light strip may preclude a clean-looking, form-fitting installation since the electrical connector can't easily match the rest of the light strip in size, shape or flex. Furthermore, an electrical connector that meets high physical and environmental protection is generally expensive. The electrical connector is a common failure point in many commercially available light strips. Some other light strip designs such as those disclosed in the '293 patent do not entirely specify the electrical connector, providing only a portion of an electrical connector, an area where an electrical connector can be attached by a professional installer, or leaving electrical connection entirely up to an installer. This may be suitable for an architectural application, but not for a high volume consumer product such as a flexible light strip for bicycles where ease of installation and use is important. Accordingly, there is a need in the art for an improved LED light Strip.